Web3 is about the decentralized web. The idea is that web1 was about static webpages, web2 was about interaction using blogs and forums. Web2 then evolved to a system dominated by huge centralized entities such as Facebook.
The blockchain is one of the major technologies enabling a decentralized infrastructure. With non-fungible tokens (NFT's) there seems to be far more mainstream traction.
However, once again a new centralizing movement could take place. In a research report discussed on Barron's, UBS says: 'Blockchains don’t scale in practice without turning into the same ‘plutocratic’ systems they were designed to replace'.
Another take on the 'scalability trilemma' can be found here 
. Meta-remark: I stumbpled upon that article via an entry on fedwiki which I discovered via fedwikiriver .
The Financial Times reported that Facebook and Instagram will allow NFT's and would help users to mint and sell them, they're considering the launch of a marketplace. While fans of decentralization may reject that, it could very well push a mainstream audience to embrace NFT's and related metaverse-applications.